EMEC - Greg

Definitions

Electromagnetism Units

Symbol	Units	Name	Definition
		Flux	A scalar value. The rate of transfer of energy (or another physical quantity) per unit area. <ref> Wiktionary - Flux </ref>
$\overrightarrow{E}$	$\frac{V}{M}$	Electric field (intensity/strength)	The space surrounding an electric charge. It will exert a force on other electrically charged objects.
$\overrightarrow{D}$	$\frac{C}{M^2}$	Electric (flux density/displacement field)	The number of lines of electric flux per unit area
$\overrightarrow{H}$	$\frac{A}{M}$	Magnetic field (intensity/strength)
$\overrightarrow{B}$	$T=\frac{W}{M^2}$	Magnetic (flux density/induction)

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Electric field lines <ref> Electric field lines</ref>

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Electric flux density <ref> Electric flux density </ref>

Analogies between Electric & Magnetic Circuits

Electric	Magnetic	Notes
$V=\int \overrightarrow{E}\overrightarrow{dl}$	$\overrightarrow{F}=\int \overrightarrow{H}\overrightarrow{dl}$
$\sum _n{V}_n=0=\oint \overrightarrow{E}\overrightarrow{dl}$	$\oint \overrightarrow{H}\overrightarrow{dl}=Ni=\sum _{n}Hl+Ni=0$	Kirchoff's voltage law, Ampere's law
$\sum _n{I}_n=0={\oint }_S\overrightarrow{J}\overrightarrow{dS}$	$\oint \overrightarrow{B}\overrightarrow{dS}=0$	Kirchoff's current law, The B-field has to go around in a loop
$\oint \overrightarrow{J}\overrightarrow{dS}=I$	$\int \overrightarrow{B}\overrightarrow{dS}=\mathrm{\Phi }$	Magnetic flux, Phi
$R=\frac{V}{I}$	$\mathfrak{\Re }=\frac{F}{\mathrm{\Phi }}=\frac{Ni}{\mathrm{\Phi }}$	Reluctance
$I=\frac{V}{R}=GV$ or $\overrightarrow{J}=\sigma \overrightarrow{E}$	$\overrightarrow{B}=\mu H$	Assumes linearity - exceptions: Hysterisis loop, etc

References

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